Abstract: A method for controlling a voltage mode controlled electric machine comprising: receiving a torque value representative of a desired torque; obtaining a speed value indicative of a rotational velocity of the electric machine; acquiring a phase advance value indicative of a desired phase advance angle; generating a voltage command responsive to the torque value, the position value; the generating is responsive to the torque value, the speed value, and the phase advance value.

Abstract: A method for implementing control signal linearization for an electric motor is disclosed. In an exemplary embodiment, the method includes receiving a desired voltage command to be applied to the motor and determining whether the magnitude of the desired voltage command falls between a first value and a second value. If the magnitude of the desired voltage command falls between the first value and the second value, then modulating a voltage command between the first and the second value over a determined sample period, thereby resulting in the application of a modulated voltage command to the motor.

Abstract: A method and apparatus for determining the velocity of a rotating device is described herein. The apparatus includes a magnet assembly affixed to a rotating shaft of a rotating device and a circuit assembly. The circuit assembly includes a circuit interconnection having a sense coil and sensors affixed thereto.

Abstract: A method and apparatus for determining the velocity of a rotating device is described herein. The apparatus includes sets of sense magnets affixed to a rotating shaft of a rotating device and a circuit assembly. The circuit assembly includes a circuit interconnection having sense coils and sensors affixed thereto. The circuit assembly is adapted to place components thereon in close proximity to the sets of sense magnets on the rotating part.

Abstract: A method and system for determining the velocity of a rotating device is described herein. The system includes an apparatus with a set of sense magnets affixed to a rotating shaft of the rotating device and a circuit assembly. The circuit assembly includes a circuit interconnection having a plurality of sense coils and sensors affixed thereto. The circuit assembly is adapted be in proximity to the set of sense magnets on the rotating part. A controller is coupled to the circuit assembly, where the controller executes an adaptive algorithm that determines the velocity of the rotating device. The algorithm is a method of combining a derived velocity with a velocity from the tachometer.

Abstract: Disclosed is a current sensing system for measuring the current flowing through a current sensing resistance. The system has a calibration resistance coupled to the current sensing resistance and a pair of input resistances each having a first end coupled to one of the ends of the current sensing resistance and a second end coupled to one of the ends of the calibration resistance. A voltage is created across the calibration resistance and the calibration resistance is set at a predetermined level to compensate for the current sensing resistance deviating from a reference value. The voltage is filtered and amplified to produce an output representative of the measured current.

Abstract: A brushless DC motor modifies motor commutation events to reduce noise by providing overlapping activation of the switch being deactivated with the switch being newly activated so that three switches are temporarily activated. The newly activated switch is pulse width modulated with a motor torque controlling duty cycle, and the switch being deactivated is pulse width modulated synchronously with the newly activated switch but with a duty cycle decreasing from the torque controlling duty cycle. The decreasing modulation of the switch being deactivated allows a slower current decrease in the phase turning off to reduce or eliminate the disturbances, and thus the noise. The decreasing modulation is preferably exponential in manner, with a time constant varying inversely with motor speed so that the duty cycle reaches a predetermined minimum in a predetermined maximum number of motor electrical degrees.

Abstract: A system and method for controlling the collisions between elements of an automotive rack and pinion steering apparatus and an end-of-travel stop is presented. The system comprises a sensor for sensing a set of dynamic variables of the rack and pinion steering apparatus and operative thereby to generate as output therefrom a first set of signals indicative of the set of dynamic variables; a controller responsive to the first set of signals and operative thereby to provide as output therefrom a modified torque assist command; and a motor drive assembly drive assembly responsive to the modified torque assist command and operative thereby to provide modified torque assistance to the rack and pinion steering apparatus. In another embodiment, the dynamic data is used to calculate a torque limit to be imposed upon the torque assist command whenever the steering system is close to end-of-stop. The two embodiments may also be superimposed.

Abstract: An electric motor actuator used in an environment of varying loads for varying time periods is efficiently designed to a predetermined specification in terms of both motor load and time and operated up to but not exceeding this specification over the full expected operating range. A motor load signal is low pass filtered with a plurality of time constants spanning a range of expected motor operation to generate a plurality of filtered motor load signals each associated with one of the time constants. Each of these filtered motor load signals is compared with a predetermined reference value corresponding to the associated time constant. If one or more of the filtered motor load signals exceeds the predetermined reference value with which it is compared, the one that so exceeds by the greatest margin is selected. A command current limit factor is derived from the selected filtered motor load signal and used to limit the commanded motor current.

Abstract: An electric power steering control for a motor vehicle reduces motor torque ripple and road generated disturbances communicated to the vehicle handwheel while promoting system stability. In deriving an output command torque signal to the EPS motor, the control (1) derives an electric motor speed signal, (2) differentiates the electric motor speed signal, (3) stores a schedule of gain as an increasing function of electric motor torque, (4) modifies the differentiated estimated electric motor speed signal in response to the gain to provide a damping correction value and (5) derives the output command signal responsive to the damping correction.

Abstract: A vehicle power steering system uses an electric motor to drive a pump at a variable speed to provide power steering fluid at a variable flow for power assist to operator steering efforts. The system has a speed control for the electric motor which derives a command speed signal from an input load signal, the speed being switched in a switching region of the power steering fluid pressure signal between a low speed for standby operation and a higher speed to supply the power steering operation demands. The system includes sensor apparatus for providing a power steering load signal and a power steering fluid temperature sensor. The speed control derives the input load signal in the switching region by modifying the power steering load signal in response to the power steering fluid temperature sensor and a motor speed signal to compensate for temperature and speed dependent losses.

Abstract: A brushless DC motor modifies motor commutation events to reduce noise by providing overlapping activation of the switch being deactivated with the switch being newly activated so that three switches are temporarily activated. The newly activated switch is pulse width modulated with a motor torque controlling duty cycle, and the switch being deactivated is pulse width modulated synchronously with the newly activated switch but with a duty cycle decreasing from the torque controlling duty cycle. The decreasing modulation of the switch being deactivated allows a slower current decrease in the phase turning off to reduce or eliminate the disturbances, and thus the noise. The decreasing modulation is preferably exponential in manner, with a time constant varying inversely with motor speed so that the duty cycle reaches a predetermined minimum in a predetermined maximum number of motor electrical degrees.

Abstract: A brushless DC motor has a permanent magnet rotor comprising p magnetic poles and a stator having an integer multiple of 6*p*n slots containing windings, n being a positive, non-zero integer, and the poles and slots being skewed by one slot pitch with respect to each other. The windings in the slots are electrically connected in two separate groups of three-phase windings with each group having three phase terminals, the windings of each group being distributed in phase belts occupying alternate sectors of 30 electrical degrees and the windings of the first group alternating with the windings of the second group. Since the trapezoidal back EMF voltage curve has a wider top it exhibits less droop, compared with an equivalent three-phase brushless DC motor of the prior art, over the 60 electrical degree period centered on maximum back EMF in which torque producing current is applied.

Abstract: A vehicle power steering system uses an electric motor to drive a pump at a variable speed to provide power steering fluid at a variable flow for power assist to operator steering efforts. The system has a speed control for the electric motor which derives a command speed signal from a power steering load signal, senses motor speed and controls electric power to the motor in response thereto to vary the speed of the electric motor in the direction of the command speed signal. In a switching region of the power steering fluid pressure signal, the speed control switches between a low speed for standby operation and a higher speed to supply the power steering operation demands. The speed control modifies the switch-point load value in response to the power steering fluid temperature sensor to compensate for temperature dependent losses. Separate switch-points are preferably provided for increasing and decreasing power steering load to provide hysteresis; and both switch-points are preferably compensated.

Abstract: An electric power steering control apparatus comprising a torque sensor coupled to a vehicle steering system for measuring steering wheel torque provided by a vehicle operator, a steering angle sensor coupled to the steering system for measuring steering wheel angle, a controller, responsive to the measured steering wheel torque and a vehicle speed, providing a sum return-to-center command, and a motor responsive to the sum return-to-center command, wherein the controller determines a low speed return-to-center command responsive to the measured steering wheel torque and a first predetermined function, determines a high speed return-to-center command responsive to the measured steering wheel torque and a second predetermined function and blends the low and high speed return-to-center commands to obtain the sum return-to-center command.